A heat map is a graphical representation of data points. Each data point is associated with a value. For example, data points regarding marathon runners may include values corresponding to finish times for the marathon runners. Different values of the data points are assigned colors. Accordingly, each data point in the heat map has a color corresponding to the value of that data point. The resulting heat map appears as a multi-colored area of all of the data points. Given the vast amounts of data that most endeavors generate and use, heat maps may be difficult to interpret. For example, a single heat map may have thousands of data points in dozens of colors. Even if the colors of each data point can be discerned, the heat map may not visually aid the viewer in identifying issues (e.g., data points, data thresholds, data trends). Thus, typical heat maps do not convey information about the represented data efficiently.